The invention relates to exercise devices, and specifically to an exercise device which is useful to strengthen the extensor muscles of the lower arm, as an aid in reducing repetitive strain injury, and particularly in reducing the carpal-tunnel syndrome form of repetitive stress injury.
A moderately active individual makes thousands of different hand movements in a single day. Such activity may lead to repetitive strain injuries, such as carpal-tunnel syndrome, in which the tendons and ligaments in the carpal tunnel swell and compress nerves, resulting in hand numbness. A similar disease is known as De Quervan's disease, which cause localized numbness in the thumb, thereby preventing thumb movement. Swelling of the tendons in the carpal tunnel may also reduce circulation to the hands, further causing numbness and pain.
Carpal-tunnel syndrome, also referred to as CTS, may be caused or aggravated by a variety of disorders, such as arthritis or pregnancy, or by drugs which cause the body to retain fluids. Additionally, individuals who spend extended periods of time with their wrist in a flexed condition may develop CTS. One cause of CTS is the continuous flexing of the wrist which is particularly common amongst individuals who spend long periods of time at keyboards, whether such keyboards be associated with computers per se, or with cash registers or other such devices. Such flexing is generally accompanied by pronation of the hand, i.e., holding the palm in a downward facing position, which further strains the connective tissue and nerves running through the carpal tunnel. Musicians are also subject to CTS, as are individuals who do a great deal of lifting. It is common in such individuals that the flexor muscles of the forearm are much stronger than the extensor muscles of the forearm, which tend to leave the wrist in a flexed condition, even when it is not necessary for the wrist to be flexed. CTS itself is caused by compression of the median nerve, which runs through the wrist and branches into the palm, thumb and first three fingers. The median nerve runs through a bony structure which is identified as the carpal tunnel. The flexor tendons and the carpal ligament in the carpal tunnel may swell due to repetitive hand movements, pinching the medial nerve and producing the condition known as CTS. CTS generally results in an inability effectively to grip with the hands, and is usually accompanied by a tingling and numbness in the fingers.
In some instances, a mild case of CTS may be mitigated by resting the wrist, or by varying its movement throughout the day. Anti-inflammatory drugs or cortisone may be given to reduce swelling. In some instances, surgery is performed to lessen CTS, however, it is very possible that the surgery may produce further swelling in the carpal tunnel, and ultimately, may aggravate the condition rather than curing it.
Repetitive Strain Injury (RSI) may occur in any part of the body. When it occurs in the hands, it can produce severe pain in the wrist and forearm, and result in reduced gripping ability in the hand.
Known exercises, such as wrist extensions, still require the flexion of the fingers to grip a weight, and do not provide resistance to the abductor or extensor muscles of the fingers. Other devices, such as the Tiger Paw.TM., provide limited resistance for the abductor muscles, but do nothing to strengthen the extensor muscles that extend the hand at the wrist.
The exercise device of the invention is intended to strengthen the extensor muscles of the fingers, hand and wrist located in the forearm and the abductor muscles of the fingers, thereby providing a balance between the extensor and flexor muscles to prevent the continuous flexing of the wrist, thereby eliminating one of the causes of CTS.